Android Open Source - PowerMonitor Main Activity

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License

The source code is released under:

Apache License

Java Source Code

package net.phfactor.powermonitor;
//from  www  .  j a va  2  s  . c  o  m
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import org.json.JSONException;
import org.json.JSONObject;

import android.app.ActionBar;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;

public class MainActivity extends FragmentActivity implements
    ActionBar.OnNavigationListener
{
  static final String TAG = "PowerMonitor";
  
  private Handler mHandler = new Handler();
  private Runnable rUpdater;
  public static TextView curPower, maxReading, difference;
  public static ProgressBar cpBar;
  public static double tareValue;
  
  /**
   * The serialization (saved instance state) Bundle key representing the
   * current dropdown position.
   */
  private static final String STATE_SELECTED_NAVIGATION_ITEM = "selected_navigation_item";

  @Override
  protected void onCreate(Bundle savedInstanceState)
  {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // Set up the action bar to show a dropdown list.
    final ActionBar actionBar = getActionBar();
    actionBar.setDisplayShowTitleEnabled(false);
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);

    // Set up the dropdown list navigation in the action bar.
    actionBar.setListNavigationCallbacks(
    // Specify a SpinnerAdapter to populate the dropdown list.
        new ArrayAdapter<String>(actionBar.getThemedContext(),
            android.R.layout.simple_list_item_1,
            android.R.id.text1, new String[] {
                getString(R.string.title_section1),
                getString(R.string.title_section2),
                getString(R.string.title_section3), }), this);
    
    // See http://android-developers.blogspot.com/2007/11/stitch-in-time.html
    rUpdater = new Runnable()
    {
      public void run()
      {
        GetReading reader = new GetReading();
        reader.execute();
        
        mHandler.postDelayed(this, Constants.UPDATE_DELAY_MSEC);
      }
    };
    
  }

  @Override
  public void onRestoreInstanceState(Bundle savedInstanceState)
  {
    // Restore the previously serialized current dropdown position.
    if (savedInstanceState.containsKey(STATE_SELECTED_NAVIGATION_ITEM))
    {
      getActionBar().setSelectedNavigationItem(
          savedInstanceState.getInt(STATE_SELECTED_NAVIGATION_ITEM));
    }
  }

  @Override
  public void onSaveInstanceState(Bundle outState)
  {
    // Serialize the current dropdown position.
    outState.putInt(STATE_SELECTED_NAVIGATION_ITEM, getActionBar()
        .getSelectedNavigationIndex());
  }

  @Override
  public boolean onCreateOptionsMenu(Menu menu)
  {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
  }

  @Override
  public boolean onNavigationItemSelected(int position, long id)
  {
    // When the given dropdown item is selected, show its contents in the
    // container view.
    Fragment fragment = new DummySectionFragment();
    Bundle args = new Bundle();
    args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, position + 1);
    fragment.setArguments(args);
    getSupportFragmentManager().beginTransaction()
        .replace(R.id.container, fragment).commit();
    return true;
  }

   /*!
      * @brief To convert the InputStream to String we use the BufferedReader.readLine()
      * method. We iterate until the BufferedReader return null which means
      * there's no more data to read. Each line will appended to a StringBuilder
      * and returned as String.
      */
  private static String convertStreamToString(InputStream is) 
  {
       BufferedReader reader = new BufferedReader(new InputStreamReader(is));
       StringBuilder sb = new StringBuilder();

       String line = null;
       try {
           while ((line = reader.readLine()) != null) {
               sb.append(line + "\n");
           }
       } catch (IOException e) {
           e.printStackTrace();
       } finally {
           try {
               is.close();
           } catch (IOException e) {
               e.printStackTrace();
           }
       }
       return sb.toString();
   }
    
  public static String syncGetUrl(String url)
  {
    HttpURLConnection connection = null;
    try
    {
      URL mURL = new URL(url);
      connection = (HttpURLConnection) mURL.openConnection();
      
      // OK, should be connected at this point, try and read the response.
      InputStream in = new BufferedInputStream(connection.getInputStream());
      String res_str = convertStreamToString(in);
      return res_str;      
    }
    catch (MalformedURLException me)
    {
      Log.e(TAG, "Bad server URL '" + url + "'");
      return null;
    }
    catch (IOException ie)
    {
      Log.e(TAG, "IO error on transfer: " + ie.getMessage());
      Log.e(TAG, "error was", ie);
      return null;
    }
    finally
    {
      if (connection != null)
        connection.disconnect();
    }    
  }
  
  public static void displayReadings(Double cur, Double rmax)
  {
    curPower.setText(String.format("%4.2f", cur));
    maxReading.setText(String.format("%4.2f", rmax));
    
    int progress = (int) ((cur / rmax) * 100.0);
    cpBar.setProgress(progress);
    
    difference.setText(String.format("%4.2f", cur- tareValue));
  }
  
  public static class GetReading extends AsyncTask<Void, Void, String>
  {
    double cp, mp;
    
    private void parseDatum(String datum)
    {
      if (datum == null)
        return;
      
      JSONObject jobj;
      try
      {
        jobj = new JSONObject(datum);
        
        JSONObject jdata = jobj.getJSONObject("strip");
        cp = jdata.getDouble("watts");
        mp = jdata.getDouble("peak");
      }
      catch (JSONException je)
      {
        Log.e(TAG, "Error parsing data");
        cp = mp = 0.0;
      }
    }
    
    @Override
    protected void onPostExecute(String result)
    {
      parseDatum(result);
      displayReadings(cp, mp);
      
      super.onPostExecute(result);
    }

    @Override
    protected String doInBackground(Void... params)
    {
      return syncGetUrl(net.phfactor.powermonitor.Constants.URL);
    }
  }
  
  @Override
  protected void onPause()
  {
    mHandler.removeCallbacks(rUpdater);
    super.onPause();
  }

  @Override
  protected void onResume()
  {
    mHandler.postDelayed(rUpdater, Constants.UPDATE_DELAY_MSEC);    
    super.onResume();
  }
  
  /**
   * A fragment representing a section of the app, but that just calls fetch/display
   */
  public static class DummySectionFragment extends Fragment implements OnClickListener
  {
    Button tare;
    /**
     * The fragment argument representing the section number for this
     * fragment.
     */
    public static final String ARG_SECTION_NUMBER = "section_number";

    public DummySectionFragment()
    {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState)
    {
      View rootView = inflater.inflate(R.layout.fragment_main_dummy,  container, false);
      
      curPower = (TextView) rootView.findViewById(R.id.curPowerTxt);
      maxReading = (TextView) rootView.findViewById(R.id.maxPowerTxt);
      difference = (TextView) rootView.findViewById(R.id.curDifference);
      cpBar = (ProgressBar) rootView.findViewById(R.id.curPowerBar);
            
      tare = (Button) rootView.findViewById(R.id.button1);
      tare.setOnClickListener(this);
      
      tareValue = 0.0;
      return rootView;
    }

    @Override
    public void onClick(View v)
    {
      if (tare != null)
        tareValue = Double.parseDouble(curPower.getText().toString());
      else
        Log.e(TAG, "null button ref");
    }
  }

}

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